Jupiter

Vital Statistics R = 71,492 km M = 1.90 x kg R orbit = x 106 km T = 124° K Eccentricity = axial tilt = 3.08° “day” = 9.84 hours “year” = years orbital inclination = 1.31° R Å M Å 5.2 A.U.

A bit of background Known since prehistoric times One of Galileo’s 4 big discoveries 63(?) moons to date moons are named for figures in the life of Zeus (mostly his lovers) faint rings gradually slowing down Io, Europa, and Ganymede are locked in a 1:2:4 orbital resonance (in a few million years, Callisto will be locked as well, with an orbit 8 times that of Io)

Claims to fame Largest planet in the solar system –so large that even causes a wobble in the sun’s motion that would be detectable from other stars Boasts the most geologically active moon in solar system Great Red Spot visible bands (even visible from Earth with backyard telescopes)

The Great Red Spot Origin is unknown A storm about 2 times Earth’s diameter Has been raging for at least 300 years (Discovered by either Cassini or Robert Hooke in the mid-17th century) gas flow around the spot is counterclockwise, with a period of about 6 days at speeds up to 2770 mph center is tranquil (like the eye of a hurricane) gas north of the spot flows westward, whereas gas south of the spot flows east

Series of pictures taken by HST between 1992 and 1999

Movie interlude look at Jupiter “Day” Rotating Jupiter Red spot

Visits Pioneer 10 in 1973 (1st visit) Pioneer 11 Voyager 1 Voyager 2 Ulysses (was really just using Jupiter for a gravity boost) Galileo

Pioneers 10 was 1st to Jupiter - just a flyby Pioneers were designed to test the ability of spacecraft to survive passage through the asteroid belt and Jupiter’s magnetosphere 11’s power supply is dead, but 10 is still functioning will be 1st craft to reach interstellar space –bear plaques trying to convince aliens we’re intelligent

Voyagers

Voyagers Voyager 1 launched Sept 5, 1977 and flew past Jupiter March 5, 1979 Voyager 2 launched Aug. 20, 1977 (before V1) and flew by Jupiter August 7, 1979 Most of what we know about the gas giants comes from Voyagers 1 and 2 Discovered –that Jupiter has complicated atmospheric dynamics, lightning, and aurorae –3 new satellites –ring system –Io has active sulfurous volcanoes

Galileo

Galileo Launched Oct 18, 1989, arrived slingshot around Venus, 2 around Earth Tested instruments while at Venus High-gain antenna didn’t open as planned, so they reprogrammed the computer to use the smaller antenna (and we got most of the data it sent) Discovered a “moon” orbiting the asteroid Ida

Galileo In 1994, could see Shoemaker-Levy 9 crash into Jupiter Spacecraft (orbiter) and probe Probe descended 95 miles, collected 58 minutes of data on weather appeared that atmosphere is dryer than we thought (but later we realized the probe had entered a hot spot) near end of 58 minutes, probe measured winds of 450 mph (melted and vaporized shortly after that)

Structure and Atmosphere Atmosphere: 86.1% H 2, 13.8% He –also: ammonia, methane, water vapor Presence of lots of H2 and He is a result of strong gravity Bright “zones” (other gas planets have them, but they’re most pronounced on Jupiter) and dark “belts”

Atmosphere Upwelling in zones, sinking in belts high pressure in zones (low in belts)

Atmosphere - Zonal flow Underlying the bands is a stable pattern of eastward and westward wind flow, known as “zonal flow” note: belts and zones are related to zonal flow pattern Note - equatorial regions of atmosphere rotate faster than the planet - average flow speed of about 85 mph (similar to Earth’s jet stream)

Atmosphere - structure None of the gases listed earlier can account for coloration We believe cloud colors are the result of complex chemical processes A model based on available data and some math Galileo probe made it to the bottom of this diagram

Internal structure This diagram is based on Voyager data and theoretical modeling

Auroras

Rings Galileo image - clearly shows radial structure that had only been hinted in Voyager images

Moons Ganymede, Callisto, Europa, Io Metis, Adrastea, Amalthea, Thebe Leda, Himalia, Lysithea, Elara, Ananke, Carme, Pasiphae, and Sinope At least 47 others, some of which have been named

27Ganymede Largest moon in Solar System Weird grooves

29Callisto Oldest, most cratered surface of any body in Solar System uniform interior of ice and rock mixture 29

30

31Io Very close to Jupiter Active volcanos

32Europa Only other body in Solar System with liquid water VERY smooth

Europa interior